On hash table based 32 bits powerpc's, the hash management code runs with
a big spinlock. It's thus important that it never causes itself a hash
fault. That code is generally safe (it does memory accesses in real mode
among other things) with the exception of the actual access to the code
itself. That is, the kernel text needs to be accessible without taking
a hash miss exceptions.
This is currently guaranteed by having a BAT register mapping part of the
linear mapping permanently, which includes the kernel text. But this is
not true if using the "nobats" kernel command line option (which can be
useful for debugging) and will not be true when using DEBUG_PAGEALLOC
implemented in a subsequent patch.
This patch fixes this by pre-faulting in the hash table pages that hit
the kernel text, and making sure we never evict such a page under hash
pressure.
Signed-off-by: Benjamin Herrenchmidt <benh@kernel.crashing.org>
arch/powerpc/mm/hash_low_32.S | 22 ++++++++++++++++++++--
arch/powerpc/mm/mem.c | 3 ---
arch/powerpc/mm/mmu_decl.h | 4 ++++
arch/powerpc/mm/pgtable_32.c | 11 +++++++----
4 files changed, 31 insertions(+), 9 deletions(-)
Signed-off-by: Paul Mackerras <paulus@samba.org>
asm-ppc64/imalloc.h is only included from files in arch/powerpc/mm.
We already have a header for mm local definitions,
arch/powerpc/mm/mmu_decl.h. Thus, this patch moves the contents of
imalloc.h into mmu_decl.h. The only exception are the definitions of
PHBS_IO_BASE, IMALLOC_BASE and IMALLOC_END. Those are moved into
pgtable.h, next to similar definitions of VMALLOC_START and
VMALLOC_SIZE.
Built for multiplatform 32bit and 64bit (ARCH=powerpc).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This moves the remaining files in arch/ppc64/mm to arch/powerpc/mm,
and arranges that we use them when compiling with ARCH=ppc64.
Signed-off-by: Paul Mackerras <paulus@samba.org>
This also creates merged versions of do_init_bootmem, paging_init
and mem_init and moves them to arch/powerpc/mm/mem.c. It gets rid
of the mem_pieces stuff.
I made memory_limit a parameter to lmb_enforce_memory_limit rather
than a global referenced by that function. This will require some
small changes to ppc64 if we want to continue building ARCH=ppc64
using the merged lmb.c.
Signed-off-by: Paul Mackerras <paulus@samba.org>
This creates the directory structure under arch/powerpc and a bunch
of Kconfig files. It does a first-cut merge of arch/powerpc/mm,
arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough
to build a 32-bit powermac kernel with ARCH=powerpc.
For now we are getting some unmerged files from arch/ppc/kernel and
arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes
to files in those directories and files outside arch/powerpc.
The boot directory is still not merged. That's going to be interesting.
Signed-off-by: Paul Mackerras <paulus@samba.org>
